import java.util.Scanner;

public class Test_3 {

    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);

        System.out.println("请输入该生的成绩");
       double score= scanner.nextDouble(); //120


        if(score>=90 && score<=100){
            System.out.println("A");
        }else if(score>=80 && score<90){
            System.out.println("B");
        }else if(score>=70 && score<80){
            System.out.println("C");
        }else if(score>=60 && score<70){
            System.out.println("D");
        }else{
            System.out.println("E");
        }


    }
}
